Electromagnetic stepping switch



United States Patent ELECTROMAGNETIC STEPPING SWITCH Walter A. Wolf, Logansport, Ind., assignor to Switches, Inc., Chicago, 111., a corporation of Indiana Application December 11, 1957, Serial No. 702,105

Claims. (Cl. 200-87) This invention relates to an electromagnetic stepping switch, and its principal object is to provide a switch of that character which is of simple and rugged construction and which is economical to manufacture.

Generally, electromagnetic stepping switches may be either (1) single-direction switches which turn completely around upon a number of steps being imparted thereto, being the remotely controlled counterpart of the familiar manually operable rosette switch, for example, or (2) of the so-called flip-flop typeof two-position switch so arranged that a stepping movement imparted to the switch in either position moves the switch to the other position, being a remotely controlled counterpart of the usual footactuated dimmer switch, for example, commonly used in motor vehicles. 1

A problem common to electromagnetic stepping switches of the two general types indicated above is en countered in translating the usual straight-line movement of the armature of the electromagnet into the combined forward and sideward'movement required to actuate the switch through the usual actuating notches or ratchet teeth. In former constructions, the actuating tip of the armature has been provided with a pawl movable laterally with respect to the armature movement, as by a pivoted or a spring action to permit the actuating tip of the pawl to move forward and back with the armature and also to move laterally in carrying out its switch-actuating function. v 7

According to the invention, the necessity for the provision of a pawl member interposed .between the actuating portion of the armature and the ratchet teeth or notches of the switch mechanism is rendered unnecessary by a mounting arrangement enabling the armature to move forward and back ina principal movement and also to move laterally as required, in combination with suitable cam surfaces for guiding the movement of the armature. Thereby, the actuating portion of the armature is simplified in construction, and the overall structure may be made smaller and more compact that heretofore.

For simplicity, it has been chosen to illustrate the invention in connection with a two-position switch of the noted flip-flop type, and as applied to a single-pole double-throw type of switch having a common input terminal and a pair of alternative output terminals.

The foregoing and other objects and features of this invention and the manner of attaining them will become more apparent, and the invention itself will be best understood, by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings comprising Figures 1 to 4, wherein:

Figure 1 shows a side view of the switch structure partly in section;

Figure 2 is a plan view of the structure of Figure 1;

'Figure 2A is a left-end view partly in section, along line 2A2A of Figure 2; and

' Figures 3 and 4 are sectional views taken along line "33 and 44 of Figure 2.

Referring first to Figure 1, the device includes frame A, electromagnet B, armature C, and switch assembly D. Frame A may conveniently be formed of a length of sheet'material, such as cold-rolled steel, to provide the base portion 2 and two upturned portions 3 and 4 for supporting respectively the armature C and the switch D.

Elcctromagnet B comprises the usual round iron core member 10, spool heads 11 and 12 with coil terminals 13 aflixed to spool head 12, and the usual electromagne t winding 15 having its ends aflixed to respective terminals 13. The electromagnet is secured to member 2 of the frame as by a countersunk screw 14 threaded into the lower end of core 10.

Armature C comprises a single piece of generally rectangular magnetic sheet material 21 of an outline shown in Figure 2, and it rests on the upper end of support member 12, being held thereon bytab 25 which passes through a circular opening 26 in the armature. Armature C is thussupported on member 3 for a hinging movement about the upper end thereof as a fulcrum, toward and away from the upper pole face of core 10 of the electromagnet B, as well as for a side-to-side movement of the armature around tab 25 as a pivot. Its movement between its normal illustrated position and an actuated position adjacent to the upper pole face of core 10 is a composite of the two noted movements according to the guiding action on the armature incidental to operation of the switch structure A and a return to its normal position, as hereinafter described. Armature C further includes actuating pin 24 which may be secured thereto as by having a press fit into an opening in rod section 23, which may be welded or brazed to the under portion of the forward tapered end of part 21.

The armature C is maintained in its normal illustrated position by tension spring 8 which interconnects hook 7 formed at the rear end of part 21 and hook 9 secured to part 3, and it is stopped in its actuated position by engagement with the upper end of stop member 5, secured to. base portion 2 as by rivets 6.

The essentially magnetic portions of the structure are frame member A, core 10, and armature member 21, which parts may be formed of cold-rolled steel or of a special magnetic grade of ferrous material, as desired. Stop member 5 may be of similar material but forms no essential part of the magnetic circuit.

Switch assembly D is contained within a housing tached by rivets 35 to portion 4 of frame A. The hous ing is illustrated as being formed, except for the insulating back wall 36 thereof, of a single piece of sheet material which may be first blanked and then folded to provide the upright wall portions 29, 30, and 31 and the bottom closurerportion 32. Portion 32, has side wings 33 and 34 which overlap the wall portions 30 and 31 to lend rigidity 'of panel 36.

For its chosen illustrated function as a flip-flop type of single pole, double-throw operation, the switch structure D includes three switch terminals, comprising common terminal 71 and alternative terminals 72 and 73 (Figures '1, 2 and 4), which are secured to the structure by being passed through openings in panel 36 and secured therein as by riveting, to appear on both sides thereof. If desired, each of these terminals may be provided with a member 74 connecting an external conductor thereto.

The switching operation with respect to fixed terminals 71-to 73 is performed by conducting plate 61 carried by insulating plate 60, to which it is aflixed as by tabs 62 (Figure 4) which extend into suitable openings in plate 60, the parts 60 and 61 being together by compression spring 52 in the assembled structure. As seen best in Figures 1 and 4, insulating plate 60 is supported for rotation on the end of fixed bearing stud 49 which passes through a suitable opening in plate 60, a larger clearance opening 63 (Figure 4) being provided in conducting plate 61. As

shown in full lines in Figure 4, in one position of the switching members plate 61 connects common terminal 71 to terminal 73, and in the other position (shown in dotted outline) connects the common terminal 71 to terminal 72.

As seen best in Figure 1, bearing stud 49 has an enlarged shoulder 50 thereon which engages wall 38 around the receiving opening through the latter, and is secured in position by the riveted head 51. Actuating assembly 40, 48 is rotatably carried on stud 49 by bearing hub 48 to which member 40 is secured, as by a force fit. The

60 and 61. The position of the switching structure wherein common member 71 is placed in electrical communicaparts are kept in position along stud 49 by compression tion with terminal 73 by plate 61 is shown in full lines in Figures 3 and 4, and the alternative position (wherein common terminal 71 is similarly placed in communication with the alternative contact member 72) is indicated in dotted outline.

Actuating pin 24 of armature assembly C is guided for movement by the side walls of opening 38 of Figures 1 and 3, which has an inverted heart shape as seen best in Figure 3. Pin 24 is normally retained at the apex of opening 38 by the normal upward thrust imparted thereto by the action of tension spring 8, and is able to move downwardly either vertically or partly vertically and partly horizontally within the confines of opening 38 when the switching mechanism C is to be actuated. Camming engagement between actuating pin 24 and the upper surface of the rotatable switch control member 40 is provided by V-notches 44 and 45 in combination with separating tooth 43 which lies between the notches.

Operation winding 15 of electromagnet B is energized through terminals 13 thereof, attracting armature 21 of assembly C. The assembly C thus moves downwardly about its fulcrum line at the top surface of upright arm 3 of frame structure A, executing such coincidental and accompanying side movement as may be imparted thereto by camming action, until the movement is stopped, as by engagement between traveling member 21 and the top surface of stop member 5. At this point, a small residual air gap should remain between the upper face of electromagnet 10 and the under side of armature member 21, to permit a ready release of the armature when the electromagnet is deenergized.

'With the switch parts in the illustrated position, the downward portion of the movement of the armature carries actuating pin 24 into engagement with that side of tooth 43 which lies adjacent to notch 44. The first contact between parts 24 and 43 may tend to rotate member -40 further in a counterclockwise direction (as viewed in Figure 3), but such movement is prevented by contact between tab 46 of member 40 and side wall 30. As a consequence, part 24 is cammed by the engaged side of tooth 43 toward the bottom of notch 44. The further armature movement is thus downward and to the right 'as viewed in Figure 3.

After pin 24 reaches the bottom of notch 44. member 40 is rotated clockwise as seen in Figure 3 to the 4 alternative position indicated in dotted outline, during the remainder of the downward and sideward movement of part 24. The noted further downward movement of the armature C is a combination of pivoting about the upper face of frame arm 3 as a fulcrum and pivoting in a horizontal plane about tab 25 as a fulcrum or pivot.

The foregoing downward movement ceases when armature member 21 engages the upper face of stop member 5, at about the same time that tab 47 of member 40 closely approaches, or engages, the inner surface of side wall 31 of the switch housing. The rotating movement of member 40 is imparted by arms 41 and 42 (counterclockwise as seen in Figure 4) to bring contact plate 61 out of engagement with fixed terminal 73 and to bring it in engagement with fixed terminal 72, the engagement with the common fixed terminal 71 being maintained since a new portion of contact plate 61 slides into engagement with the latter terminal.

When electromagnet B is next deenergized, the tractive force on armature assembly C is terminated, causing the armature to be moved upwardly by spring 8 about the upper face of arm 3 as a fulcrum toward the normal illustrated position. When member 24 strikes the sloping portion of the camming opening 38 in wall 29, the upward movement continues as a combination of vertical and horizontal movement until the part 24 is cammed into its illustrated normal position at the apex of the opening.

Upon the next succeeding energization of electromagnet B, armature assembly C is again moved downwardly with results as previously described except that, with the switch parts in their alternative position indicated in dotted outline in Figures 3 and 4, actuating pin 24 strikes the side of tooth 43 which is adjacent notch 45, causing the sideward component of the downward movement of armature assembly C and actuating pin 24 to bring pin 24 in the opposite sideward direction to the bottom of actuating notch 45, following which further downward movement of the armature assembly returns the switch parts to their position indicated in full lines in Figures 3 and 4.

The next ensuing deenergization of electromagnet B permits the armature assembly to move upward until the camming surface of opening 38 overlying notch 45 is encountered, following which a sideward component of movement is introduced to bring actuating pin 24 back to its illustrated normal position.

Successive energizations of electromagnet B causes the foregoing cycle of operations to be repeated.

It will be evident that the general principles of construction and operation of the electromagnet as herein described can be applied to the actuation of a stepping device which may take three or more steps all in the same direction to execute a cycle of operations, such as for a switch having an olf position and at least two on positions.

While I have described above the principles of my in vention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention.

I claim:

1. An electromagnetic stepping-switch structure comprising an electromagnet having a tractive pole face, an armature for the electromagnet, means biasing the armature to stand normally away from the poleface, means fixed with the electromagnet for mounting the armature for movement responsive to energization and deenergization of the electromagnet, such movement comprising (1) a primary turning movement toward and away from the pole face about a first fulcrum line laterally displaced tions and mounted for rotation about an axis generally aligned with the pole face and the fulcruming means, the armature having a fixed starting position for its primary movement in one direction, ratchet means carried by the switching member and engageable by the armature during a primary movement away from the starting position to move the switching member from the position it currently occupies to its next position, the armature being caused to undergo a forward secondary movement by its engagement with the ratchet means during the said interpositional rotation of the switching member, and guide means fixed with the electromagnet and engageable by the armature during its return primary movement in the opposite direction for causing the armature to undergo a reverse secondary movement which returns the armature to its fixed starting position, whereby it is again in readiness to move the switching member from its occupied position to the next one when the armature is next moved from its starting position.

2. A structure according to claim 1, which includes a strip-like frame of magnetic material which supports the said armature at one end of the frame and supports the said switching device at the other end of the frame, the said electromagnet comprising an upstanding wound core fixed at one end to an intermediate portion of the frame member, with the other end of the core providing the said tractive pole face, the armature-supporting end of the frame comprising an upstanding end portion having a top edge which supports the armature and defines the said first fulcrum line, a pivot member fixed with the frame and extending upwardly from an intermediate portion of the said top edge to define the said second fulcrum line, the armature extendingralong the frame above the first fulcrum line and the pole face and having an opening freely receiving the pivot member, a part fixed with the armature overhanging outwardly beyond the said top edge, and a spring extending between the frame and the last said part to comprise the said biasing means.

3. A structure according to.claim 2, wherein the armatune comprises a plate-like portion overlying the said first fulcrum line and the pole face and stopping short of the said ratchet means of the said switching member, the armature further comprising a pin-like extension fixed therewith and serving to effect the said engagement and operation of the said ratchet means and to elI'ect the said engagement with the said guide means.

4. An electromagnetic stepping-switch structure com- 1 prising a frame supporting an electromagnet having an fulcrum line for the said one end of the armature, inter secting the primary fulcrum line generally at right angles thereto and to the said longest dimension of the armature,

about which fulcrum line the armature is also rotatable sideward when urged so to do, a two-position switch supported by the frame in operative relationship to the armature, the switch including a drive portion mounted for a back-and-forth rotary movement between the two switch positions about an axis generally aligned with the armature, the armature having an actuating portion generally aligned with the said axis, the drive portion having V- notches corresponding respectively to the two switch positions, the notches being so related to the switch positions that the said movement of the armature in one direction when the switch is in one said position brings the actuating portion of the armature within the notch corresponding to the other position of the switch, further movement .of the armature in the same primary direction causing the armature to move sideward out of alignment with the said axis to engage the bottom of the notch and to move the switch to its other position, and means fixed with the frame providing an inverted V-notch which restores the armature and attached actuating portion to general alignment with the said axis upon the return movement of the armature.

5. A structure according to claim 4, wherein the said movement of the armature which actuates the drive portion of the switch is toward the energized electromagnet, and a bias spring for inducing restoring movement of the armature away from the deenergized eleotromagnet.

References Cited in the file of this patent UNITED STATES PATENTS 2,221,963 Case et a1 Nov. 19, 1940 "2,271,603 Murphy Feb. 3, 1942 2,466,292 Wolf Apr. 5, 1949 2,813,949 Klein Nov. 19, 1957 FOREIGN PATENTS 663,690 France Apr. 9, 1929 824,081 Germany Dec. 10, 1951 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIGN Patent 2,912,537 November 10 1959 Walter Aa Wolf It is hereby; certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 53, for "that heretofore" read ther heretofore 3 column 4, line 48, after flenergizations" insert .asand deenergizations o Signed and sealed this 3rd day of May 1960- (SEAL) Attest; v 1 KARL H. AXLINE ROBERT c. WATSON Commissioner of Patents Attesting Officer UNITED STATES PATENT OFFICE CERTIFICATE OF CORR ECTEON Patent No. 2,912,537 November m 1959 Walter A, Wolf It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should reed as corrected below.

Column 1, line 53, for "that heretofore" read then heretofore column 4, line 48, after energizations" insert es. and deenergizations 0 Signed and sealed this 3rd day of May 1960,-

(SEAL) Attest KARL H. AXLINE Q ROBERT c. WATSON Attesting Officer v i Commissioner of Patents 

